Field
The present invention relates to an alkali metal thermal to electric converter (AMTEC) unit cell, and more particularly to an open internal electrode AMTEC unit cell which has an internal electrode of which a portion is open to the outside and thus is capable of connecting the internal electrode to an external electrode at the outside thereof, without directly collecting electricity within the AMTEC unit cell, a method for manufacturing the AMTEC unit cell and an electrically connecting method in the AMTEC unit cell.
Description of Related Art
The development of alkali metal thermal to electric converter (AMTEC) technology has started for the purpose of a power source for space. The AMTEC has a high power density per unit area and high efficiency, and maintains stability. The AMTEC uses a variety of heat sources, for example, solar energy, fossil fuel, waste heat, terrestrial heat, nuclear reactor, etc. The AMTEC is comprised of power generation cells capable of generating electricity without using a driver such as a turbine, a motor or the like, so that it can directly generate electricity from a portion contacting with the heat. When the AMTEC is formed in the form of a module in series or in parallel, a great amount of electricity of several KW to several hundredths MW can be generated. At present, through a technology of collecting the waste heat, the waste heat is collected in the form of heat water, combustion air, etc., by using a heat exchanger, a waste heat boiler or the like. The AMTEC is capable of improving the efficiency by directly generating high-quality electricity. Therefore, the AMTEC is now issued as a promising technology replacing the existing technologies.
The process of generating electricity in the AMTEC will be specifically described. After the state of Na vapor is changed into a vapor state in a high temperature and high pressure evaporator by a heat source, Na+ passes through beta-alumina solid electrolyte (BASE), and free electrons return to an anode through an electric load from a cathode, and then are recombined with ion generated from the surface of a low temperature and low pressure BETA and then is neutralized. Electricity is generated during this process.
The vapor pressure of Na plays the most significant role in a thermal conversion generator as an energy source or a driving force which generates electricity. Also, free electrons generated during a process in which Na passes through the solid electrolyte due to a concentration difference and temperature difference of a working fluid are collected through electrodes, so that electricity can be generated.
The beta-alumina and Na super-ionic conductor (NASICON) may be used as the solid electrolyte. The beta-alumina includes two kinds of beta′-alumina and beta″-alumina. The beta″-alumina has a more improved layer structure so that the conductivity of the Na+ ion is much better. Therefore, the beta″-alumina is now generally used.
In the publication of Korean Patent Application No. 10-2011-0135291, disclosed is a unit thermal conversion power generator and a thermal conversion power generation system including: a case including a first end and a second end; a working fluid disposed within the case; a solid electrolyte partitioning the inside of the case; a first electrode disposed on one side of the solid electrolyte; a second electrode disposed on one other side of the solid electrolyte; and a heat source heating alternately the first end and the second end. The invention uses an electric collector for collecting electrons generated from the electrode and the heat source works alternately on the lower and upper ends.